Field of the Invention
The present invention relates to a coil component and a manufacturing method therefor and, more particularly, to a coil component suitably used for a power supply circuit and a manufacturing method therefor. The preset invention further relates to a circuit board on which such a coil component is mounted.
Description of Related Art
In a coil component used in a power supply circuit, a current higher than that in a coil component for signal transmission flows, so that the coil component used in a power supply circuit needs to have a lower DC resistance. To reduce a DC resistance, it is necessary to reduce a coil length and to increase the cross-sectional area of a coil conductor. On the other hand, to ensure a sufficient inductance, it is necessary to increase a coil length and to reduce a coil conductor width so as to form a larger loop. Thus, a trade-off relationship exists between the reduction in the DC resistance and ensuring of the inductance.
Japanese Patent No. 5,668,849 describes a coil component for signal transmission. The coil component described in this document is designed to be used for signal transmission, so that it has a thin coil conductor and is thus not suitable for power supply use. In addition, the coil component described in this document has a structure where a conductive pattern is formed on the surface of a laminated insulating layer, so that it has low connection reliability and is thus not suitable for a power supply circuit in which high current flows.